Most current bioaffinity studies involve monitoring the analyte or target in solution with the recognizing (probe) species immobilized onto the SPR sensor chip. The injected sample plug is diverted to the SPR flow cell by a carrier (buffer) solution, while the change in the SPR signal is monitored as a function of time.
The resultant SPR-time curve (sensorgram) can then be used to extract the binding constant between the probe and the target. In many cases, a Langmuir isotherm is used to simulate a series of SPR-time curves obtained at different analyte concentrations. The simulation will yield the association (ka) and dissociation (kd) constants and binding affinity (KD).
